The long-term objective of this research is to reduce youth participation in health risk behavior. Children are vulnerable to the initiation of health-risk behaviors as they move from childhood to young adolescence. Participation in activities that may result in injury, addiction, or disease has far-reaching health implications. A model for reducing health-risk behavior is proposed that is based on Ecological Risk and Protective Theory. According to the model, an intervention that promotes positive parent-child communication should result in reduced health-risk behavior. In a previous study, the intervention, Mission Possible: Parents and Kids Who Listen (MP), a multi-family, six-week program focusing on both adults and youths as dyads, had beneficial effects on adult-youth communication. In that study, however, health-risk behavior was not examined, nor was the intervention targeted to youth transitioning from elementary school to middle school. The first aim, then, is to test the effect of MP on adult-youth communication and on health-risk behavior among youths following the transition to middle school. The second aim is to test a model wherein adult-youth communication mediates the effects of risk and protective processes on health risk behavior in late childhood and young adolescence. The model will be tested over a period of three years that includes the youth's transition to middle school. Though little systematic national data exist on the prevalence of health risk behavior among elementary school aged children, studies have suggested an alarming rate of participation. Thus, the third aim is to document health risk behavior participation among 10 to 13 year old children (5th through 8th grade). A 2-group pre-test post-test repeated measures design is proposed. In this design, random assignment of public elementary schools in 2 cities (Madison & Milwaukee, WI) to comparison or intervention conditions, stratified on race, is used to obtain 480 adult-youth dyads. The proximal outcomes/mediating variables are positive parent-child communication family Satisfaction, Open Communication, Problem-Solving Ability, and Family Caring) and selected individual, family, and environment factors. The intermediate outcome/dependent variable is children's participation in health-risk behaviors. Observations will occur over 6 waves of data collection to test for lag effect or maintenance of the intervention effect over time and to allow sufficient time for the child to have experienced additional developmental change. Hierarchical modeling will be used to test the effects of the intervention and the mediational processes.